SAN FRANCISCO , California -LRB- CNN -RRB- -- The owner of Luscious Garage is wondering whether the electric wall outlet will be the `` gas tank '' of the future .

A Toyota Prius hybrid , owned by Luscious Garage , has been converted to run on electricity .

Drivers of gas-sipping hybrid vehicles are increasingly interested in converting their vehicles from gasoline powered to electric , according to garage owner and lead technician Carolyn Coquillette .

While drivers of conventional gasoline-powered vehicles complain about higher fuel prices , clients of the San Francisco garage are investing big bucks to make their green cars even greener .

That 's being done through plug-in conversions and adding more powerful batteries to currently available gasoline/electric hybrid cars , such as the Toyota Prius .

`` The regular Prius is a gasoline dependent car ; it does n't get energy from anywhere but the gas tank , '' said Coquillette .

`` What this -LSB- conversion -RSB- allows me to do is get energy through an -LSB- electric wall -RSB- outlet , so -LSB- the wall outlet -RSB- is like my electric gas tank , '' she said .

Coquillette , who has degrees in physics and English , said she gets three or four calls or e-mails a day , asking about the conversion . And , she says , with gas prices at more than $ 4 per gallon , she expects even more interest .

A lot of the cars that pull in to Luscious Garage are Toyota Prius hybrids , which Coquillette calls , `` the Volkswagen Beetle of our times . ''

Coquillette showed off the garage 's psychedelically painted Prius , which has undergone the conversion .

Its original nickel-metal-hydride battery packs have been replaced with lead acid batteries to extend the distance the car can travel on electricity . Coquillette expects to begin conversions to even more efficient lithium batteries soon .

The plug-in conversion costs about $ 7,500 .

`` Gas becomes optional , '' with this conversion , Coquillette said . `` Gas is n't required to move this car anymore . If you want to drive a really long way , without recharging , yes , gas is required , but it gives you the flexibility of not having to burn gas anymore if you do n't want to . And that 's very liberating , '' she said .

The garage itself strives to be green , with much of its power coming from solar panels .

And with gasoline approaching $ 5 per gallon in the San Francisco Bay area , `` plugging in cars make a whole lot of sense right at the pocketbook , '' said Korthof , who works for Energy Efficiency Solar .

What kind of people are converting to this conversion ?

`` We 've seen such a diverse group of people , '' said Coquillette . `` We have some people who come in who are entrepreneurs , who are business people , there are some people who are diehard environmentalists , but there are some people who come in , they just want to burn less gas . ''

The corporate folks at Toyota do n't have any official position on plug-in conversions . They do n't endorse or discourage it . iReport.com : Show us your first car

But for hybrid owners who demonstrate exuberant efforts to find more energy efficiency , `` we really appreciate the fact that the Prius is the vehicle of choice , '' said Jana Hartline , environmental communications manager for Toyota .

Hartline said the Prius was not designed with any conversion possibilities in mind , but she said the company welcomes any technology that pushes the envelope on plug-in batteries .

While the nickel metal hydride -LRB- Ni-MH -RRB- battery will remain the choice for Prius , Camry and Highlander hybrids , Toyota is doing some research and development with lithium ion batteries .

Hartline said Toyota will be using lithium ion batteries in some commercial fleets in late 2009 , mostly to learn more about charging behaviors .

Although the current batteries are `` durable and reliable , '' Hartline said lithium ion batteries pack more energy into a smaller space .

Much more research is needed , she said , about how hybrid owners would use their vehicles . For example , how often and for how long owners would plug in to the electrical grid , or a solar supply .

Also , as more drivers become interested in alternative energy , they will need to learn more about infrastructure .

For example :

• Will companies , malls or fast-food joints provide charging stations ? • Will they charge for the charge ? • In what other ways will the energy infrastructure have to change ?

While the 2004-2008 Prius is the most popular hybrid conversion , it is also possible on 2005-2008 Mercury Mariner and Ford Escape hybrids .

And , as Coquillette says on the Luscious Garage Web site , `` Any car can become a plug-in hybrid , if you have enough money . ''

And driven customers do n't seem to be letting cost discourage them from the conversion .

`` Customers are not coming to me and saying , ` I 'll do this if there is a rebate . ' People come to me and say , ' I want to do this right away , ' '' said Coquillette .

Luscious Garage will soon open a second location for the growing number of really green hybrid owners .

`` Hybrid technology is one thing . Then there is plug-in hybrid technology , which is the next step , which genuinely removes your dependence on fossil fuel , '' said Coquillette .

However , most U.S. electricity is created from burning fossil fuels -- about 70 percent , according to the U.S. Energy Information Agency of the Department of Energy . Just under 49 percent comes from coal-burning power plants , about 20 percent from natural gas and about 1 1/2 percent from burning oil .

CNN 's Peter Dykstra and Miles O'Brien contributed to this report .

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San Francisco garage converts hybrid vehicles to plug-in electric power

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For $ 7,500 , Luscious Garage converts Prius , Mariner , Escape models

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How will battery-powered vehicles change the nation 's fuel infrastructure ?

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Electric cars do n't pollute , but much U.S. electricity comes from fossil fuels